Method and apparatus for transmitting/receiving system information in broadband wireless communication system

ABSTRACT

A method and an apparatus for transmitting and receiving System Information (SI) of a femto base station in a wireless communication system are provided. In the method, an SI transmission point is determined using unique identification information of a femto base station itself and unique identification information of a macro base station with which the femto base station is associated. Each of user equipment and the macro base station generate a measurement gap pattern representing an SI reception point using the unique identification information of the femto base station and the unique identification information of the macro base station. SI is received from the femto base station according to the generated measurement gap pattern.

PRIORITY

This application claims the benefit under 35 U.S.C. §119(a) of a Koreanpatent application filed in the Korean Intellectual Property Office onApr. 30, 2008 and assigned Serial No. 10-2008-0040501, the entiredisclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a broadband wireless communicationsystem. More particularly, the present invention relates to a method andan apparatus for transmitting/receiving System Information (SI)including a Global Cell IDentifier (GCID) of a femto base station.

2. Description of the Related Art

In a cellular wireless communication system, a channel may deterioratedue to one or more of a geographical factor inside a cell, a distancebetween User Equipment (UE) and a base station, and movement of the UE,so that communication between the UE and the base station is hampered.More particularly, when a UE is located inside a closed building such asan office or a household, a channel between a base station and the UEmay be deteriorated in a region referred to as a shadow region. The UElocated in the shadow region has difficulty in communicating with thebase station.

A pico cell concept is being proposed to provide a service to the indoorshadow region, and a femto cell concept is being proposed to provide adata service of a far higher level to even more users while addressing aservice limitation of the indoor shadow region. The femto cell has asmaller coverage area then that of a macro cell. A plurality of femtocells may be installed inside one macro cell area.

As a plurality of femto cells are installed inside one macro cell areaas described above, a Physical Cell IDentifier (referred to as ‘PCID’hereinafter) which is one of identifiers identifying the femto cell maybe repeatedly used inside one macro cell area. That is, since 3rdGeneration Partnership Project (3GPP) and 3GPP2 standards allow for areuse of the PCID, two or more femto cells included inside one macrocell area may have the same PCID. Therefore, the macro cell cannotidentify a femto cell of a relevant cell using only a PCID of anadjacent cell reported by a UE.

Therefore, a method of allowing each femto cell to report the PCID and aGlobal Cell IDentifier (GCID) together is being discussed, and, a methodof allowing a UE to obtain the GCID from a femto cell is beingdiscussed.

The GCID is included in System Information (SI) that includesinformation of a relevant femto cell and is transmitted, and each UEreceives the SI during a predefined measurement gap assigned for cellsearching by a serving base station.

The conventional art provides two techniques for receiving SI from abase station of the femto cell. One is a technique of lengthening ameasurement gap and increasing a probability that SI is received for thelengthened gap. However, it is difficult to use this technique when atime of suspending data transmission/reception is not as long as in aVoice over Internet Protocol (VoIP).

The other is a technique of requesting and receiving a separatemeasurement gap pattern from a base station of a macro cell in order tosearch for the base station of the femto cell. For this purpose, asignaling message exchange as illustrated in FIG. 1 is used.

FIG. 1 is a view illustrating a signal flow for reception of SI in aconventional broadband wireless communication system. Referring to FIG.1, in step 110, UE 100 determines if a measurement gap pattern forreceiving SI is needed. In step 112, the UE 100 requests a macro basestation (macro eNB) 104 to transmit the measurement gap pattern. In step114, the macro base station 104 generates the measurement gap patternfor the SI using information of a relevant femto base station, and instep 116, transmits the generated measurement gap pattern to the UE 100.In step 118, the UE 100 searches for neighboring femto base stationsduring the measurement gap. In step 120, the UE 100 enters a region of afemto base station (femto eNB) 102 identified during the search. In step122, the UE 100 receives SI transmitted from the femto base station 102during the measurement gap.

As described above, the technique of being assigned the measurement gappattern requires a signaling exchange between a macro base station andUE. When the macro base station does not have information for a relevantfemto base station, the technique additionally requires a signalingexchange (210) between a macro base station (macro eNB) 202 and therelevant femto base station (femto eNB) 200 as illustrated in FIG. 2.FIG. 2 is a detailed view illustrating a signal flow for reception of SIin a conventional broadband wireless communication system. That is,since the technique of being assigned the measurement gap patternrequires signaling between the macro base station and the femto basestation in addition to signaling between the UE and the macro basestation, an additional delay may occur during a handover.

Therefore, there is a need for a new technique which may receive SI evenwhen there is a short amount of time for suspendingtransmission/reception, and which does not require a complicatedsignaling message exchange.

SUMMARY OF THE INVENTION

An aspect of the present invention is to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentinvention is to provide a method and an apparatus fortransmitting/receiving system information including a Global CellIDentifier (GCID) of a femto base station in a broadband wirelesscommunication system.

Another aspect of the present invention is to provide a method and anapparatus for determining a System Information (SI) reception pointwithout a separate signaling message exchange in a broadband wirelesscommunication system.

Still another aspect of the present invention is to provide a method andan apparatus for determining an SI transmission point of a femto basestation using unique identification information of a macro base stationand unique identification information of the femto base station in abroadband wireless communication system.

Yet another aspect of the present invention is to provide a method andan apparatus for generating a measurement gap pattern representing an SIreception point of a femto base station in a broadband wirelesscommunication system.

In accordance with an aspect of the present invention, an SItransmission method of a femto base station in a wireless communicationsystem is provided. The method includes receiving unique identificationinformation of a macro base station with which a femto base station isassociated, determining an SI transmission point using uniqueidentification information of the femto base station itself and thereceived unique identification information of the macro base station,and transmitting SI including a GCID every SI transmission point.

In accordance with another aspect of the present invention, ameasurement gap pattern transmission method of a macro base station, forinforming user equipment of an SI transmission point of a femto basestation in a wireless communication system is provided. The methodincludes receiving unique identification information of at least onefemto base station included in a Closed Subscriber Group (CSG) from theuser equipment, generating at least one measurement gap patternrepresenting a point at which SI of the at least one femto base stationis transmitted using unique identification information of the macro basestation itself and the unique identification information of the at leastone femto base station, and transmitting the generated at least onemeasurement gap pattern to the user equipment.

In accordance with still another aspect of the present invention, amethod of user equipment which receives SI of a femto base station in awireless communication system is provided. The method includestransmitting unique identification information of at least one femtobase station included in a CSG to a macro base station, generating atleast one measurement gap pattern representing an SI reception pointusing unique identification information of the macro base station andthe unique identification information of the at least one femto basestation, and receiving SI from the at least one femto base stationaccording to the generated at least one measurement gap pattern.

In accordance with further another aspect of the present invention, anSI transmission apparatus of a femto base station in a wirelesscommunication system is provided. The apparatus includes a receiver forreceiving unique identification information of a macro base station withwhich a femto base station is associated, a transmission pointdeterminer for determining an SI transmission point using uniqueidentification information of the femto base station itself and thereceived unique identification information of the macro base station,and a transmitter for transmitting SI including a GCID every SItransmission point.

In accordance with yet another aspect of the present invention, ameasurement gap pattern transmission apparatus of a macro base station,for informing user equipment of an SI transmission point of a femto basestation in a wireless communication system is provided. The apparatusincludes a receiver for receiving unique identification information ofat least one femto base station included in a CSG from a user equipment,a measurement gap pattern generator for generating at least onemeasurement gap pattern representing a point at which SI of the at leastone femto base station is transmitted using unique identificationinformation of the macro base station itself and the uniqueidentification information of the at least one femto base station, and atransmitter for transmitting the generated at least one measurement gappattern to the user equipment.

In accordance with yet further another aspect of the present invention,an apparatus of user equipment which receives SI of a femto base stationin a wireless communication system is provided. The apparatus includes atransmitter for transmitting unique identification information of atleast one femto base station included in a CSG to a macro base station,a measurement gap pattern generator for generating at least onemeasurement gap pattern representing an SI reception point using uniqueidentification information of the macro base station and the uniqueidentification information of the at least one femto base station, and areceiver for receiving SI from the at least one femto base stationaccording to the generated at least one measurement gap pattern.

Other aspects, advantages, and salient features of the invention willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of certainexemplary embodiments of the present invention will be more apparentfrom the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a view illustrating a signal flow for reception of SystemInformation (SI) in a conventional broadband wireless communicationsystem;

FIG. 2 is a detailed view illustrating a signal flow for reception of SIin a conventional broadband wireless communication system; and

FIG. 3 is a view illustrating a signal flow for reception of SI in abroadband wireless communication system according to an exemplaryembodiment of the present invention;

FIG. 4 is a view illustrating an example of a measurement gap patternfor receiving SI in a broadband wireless communication system accordingto an exemplary embodiment of the present invention;

FIG. 5 is a flowchart illustrating an operation procedure of a femtobase station that transmits SI in a broadband wireless communicationsystem according to an exemplary embodiment of the present invention;

FIG. 6 is a flowchart illustrating an operation procedure of a macrobase station that generates a measurement gap for receiving SI of a UserEquipment (UE) in a broadband wireless communication system according toan exemplary embodiment of the present invention;

FIG. 7 is a flowchart illustrating an operation procedure of a UE thatgenerates a measurement gap for receiving SI in a broadband wirelesscommunication system according to an exemplary embodiment of the presentinvention;

FIG. 8 is a view illustrating a signal flow for reception of SI in abroadband wireless communication system according to an exemplaryembodiment of the present invention;

FIG. 9 is a block diagram illustrating a femto base station in abroadband wireless communication system according to an exemplaryembodiment of the present invention;

FIG. 10 is a block diagram illustrating a macro base station in abroadband wireless communication system according to an exemplaryembodiment of the present invention; and

FIG. 11 is a block diagram illustrating a UE in a broadband wirelesscommunication system according to an exemplary embodiment of the presentinvention.

Throughout the drawings, it should be noted that like reference numbersare used to depict the same or similar elements, features andstructures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of exemplaryembodiments of the invention as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the embodiments described hereincan be made without departing from the scope and spirit of theinvention. Also, descriptions of well-known functions and constructionsare omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of theinvention. Accordingly, it should be apparent to those skilled in theart that the following description of exemplary embodiments of thepresent invention are provided for illustration purpose only and not forthe purpose of limiting the invention as defined by the appended claimsand their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

By the term “substantially” it is meant that the recited characteristic,parameter, or value need not be achieved exactly, but that deviations orvariations, including for example, tolerances, measurement error,measurement accuracy limitations and other factors known to skill in theart, may occur in amounts that do not preclude the effect thecharacteristic was intended to provide.

Exemplary embodiments of the present invention provide a method and anapparatus for determining a System Information (SI) transmission pointof a femto base station based on unique identification information of afemto base station (femto eNB or home eNB) and a macro base station(macro eNB), and generating a measurement gap pattern representing an SIreception point in a broadband wireless communication system.Hereinafter, an Orthogonal Frequency Division Multiplexing (OFDM) systemis illustrated by way of example. Note that exemplary embodiments of thepresent invention are applicable to a communication system which uses adifferent scheme such as Code Division Multiple Access (CDMA).

In exemplary embodiments of the present invention, it is assumed that aUser Equipment (UE) stores a unique IDentifier (ID) of a femto basestation which is associated with a Closed Subscriber Group (CSG) and anaccess allowance list (white list or fingerprint) representing a uniqueID of a macro base station including the femto base station. Here, theCSG includes femto base stations which the UE may enter.

In addition, in exemplary embodiments of the present invention, it isassumed that frames of the UE, the femto base station, and the macrobase station are synchronized. Here, it is assumed that a frame of thefemto base station is synchronized with a frame of the macro basestation with which the femto base station itself is associated. Also, itis assumed that when the UE enters a macro base station including afemto base station corresponding to the CSG, a frame of the UE issynchronized with a frame of the relevant macro base station. At thispoint, frame synchronization indicates that index numbers of framescurrently transmitted/received are matched with each other, and theframe index is recognized in a Media Access Control (MAC) layer as wellas in a physical layer.

An exemplary embodiment of the present invention provides a method thatincludes a process of determining an SI transmission point at a pointwhere a femto base station is installed, and a process where a UE entersa macro base station and generates a measurement gap pattern forreceiving SI. The method is described with reference to FIG. 3.

FIG. 3 is a view illustrating a signal flow for reception of SI in abroadband wireless communication system according to an exemplaryembodiment of the present invention.

Referring to FIG. 3, in step 310, when a femto base station 302 isinstalled, the femto base station 302 and a macro base station 304including the femto base station 302 have their frames synchronized. Instep 312, the macro base station 304 transmits its unique ID informationto the femto base station 302. In step 314, the femto base station 302,which has received the unique ID information of the macro base station304, determines an SI transmission point, i.e., a transmission frameindex using unique ID information of the femto base station itself 302and the received unique ID information of the macro base station 304.Here, the unique ID information of the femto base station includes aGlobal Cell IDentifier (GCID), a CSG ID, and a Tracking Area IDentifier(TA ID), and may include information which combines the GCID, CSG ID,and TA ID. In addition, the unique ID information of the macro basestation includes a GCID, a PCID, and a TA ID, and may includeinformation that combines the GCID, PCID, and TA ID. In addition, theCSG ID denotes a femto base station group that a UE may enter. The TA IDdenotes a region on which a relevant femto base station can performpaging.

In addition, a transmission frame index of the SI is determined througha predefined equation. At this point, any equation is applicable as faras it is an equation that uses unique IDs of the femto base station andthe macro base station. For example, when a frame index is in the rangeof 0 to N−1, the transmission frame index may be determined usingEquation (1) below.

(CSG ID of femto base station+PCID of macro base station)modulo N   (1)

In Equation (1), N denotes a number of frames.

The femto base station 302, which has determined the transmission pointof the SI as described above, should transmit the SI at the determinedtransmission point. Here, the macro base station 304 stores in advancethe equation for determining the transmission point of the SI and thusmay recognize the transmission point of the SI by receiving the uniqueID information of the femto base station while the femto base station isinstalled, but after the installation of the femto base station iscompleted, the macro base station 304 may discard the unique ID of thefemto base station and transmission point information without storingthem. Thereby, a load increase of the macro base station may beprevented.

After the femto base station is installed, in step 320, the UE 300including the femto base station 302 as a CSG enters the macro basestation 304 including the femto base station 302. In step 322, the UEtransmits, to the macro base station 304, CSG information, i.e., aregistration message including information of femto base stations (forexample, unique ID information) which the UE can access. In step 324,the UE 300 and the macro base station 304 have their framessynchronized. In steps 326 and 328, the UE 300 and the macro basestation 304 determine a transmission frame index of SI for each femtobase station using unique IDs of femto base stations included in the CSGand a unique ID of the macro base station 304, and generate ameasurement gap pattern for receiving the SI based on the transmissionframe index, respectively. At this point, the measurement gap patternmay be generated to include only a frame having the transmission frameindex, or to further include other frames besides the frame having thetransmission frame index with consideration of an error in framesynchronization. Here, since the UE 300 and the macro base station 304generate the measurement gap patterns, respectively, in substantiallythe same way, the UE 300 is implicitly assigned a measurement gap forreception of SI by the femto base station 302.

In step 330, the UE 300 searches for a relevant femto base station 302during the measurement gap. In step 332, the UE 300 enters a region ofthe femto base station 302. In step 334, the UE receives the SIincluding a GCID from the femto base station 302 during the measurementgap.

FIG. 4 is a view illustrating an example of a measurement gap patternfor receiving SI in a broadband wireless communication system accordingto an exemplary embodiment of the present invention. As illustrated inFIG. 4, when there exists a femto base station HeNB 1 where atransmission point of SI is a frame index 0 (401 and 403), a femto basestation HeNB 2 where a transmission point of SI is a frame index 1 (411and 413), and a UE enters a macro cell included in a CSG cell 431, theUE generates a measurement gap pattern suitable for a transmission pointof HeNB 2, which is a femto base station belonging to a CSG of the UEitself, and receives the SI from the HeNB 2. Here, though the UE hasgenerated the measurement gap pattern in order to receive the SI duringframes 421, 423, and 425 having indexes of 0 to 2 with consideration ofan error in frame synchronization, the UE may generate the measurementgap pattern in order to receive the SI during only a frame having anindex 1 without consideration of an error in the frame synchronization.

FIG. 5 is a flowchart illustrating an operation procedure of a femtobase station that transmits SI in a broadband wireless communicationsystem according to an exemplary embodiment of the present invention.The operation of FIG. 5 is performed at a point where the femto basestation is installed.

Referring to FIG. 5, in step 501, the femto base station has its framesynchronized with a frame of a macro base station with which the femtobase station is associated, and in step 503, receives unique IDinformation of the macro base station from the macro base station.

In step 505, the femto base station determines a transmission point ofSI, i.e., a transmission frame index according to a predefined equationusing unique ID information of the femto base station itself and theunique ID information of the macro base station. Here, the unique IDinformation of the femto base station includes a GCID, a CSG ID, and aTA ID, and may include information which combines the GCID, CSG ID, andTA ID. In addition, the unique ID information of the macro base stationincludes a GCID, a PCID, and a TA ID, and may include information thatcombines the GCID, PCID, and TA ID.

In step 507, the femto base station transmits SI including a GCID of thefemto base station itself every transmission frame corresponding to thedetermined transmission frame index, and then ends the operationaccording to an exemplary embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation procedure of a macrobase station that generates a measurement gap for receiving SI of a UEin a broadband wireless communication system according to an exemplaryembodiment of the present invention.

Referring to FIG. 6, in step 601, a new UE having a femto base stationthat is associated with the macro base station as a CSG enters. In step603, the macro base station receives a registration message includingCSG information, i.e., information of femto base stations that the UEcan access from the UE.

In step 605, the macro base station has its frame synchronized with aframe of the UE, and in step 607, determines a transmission frame indexof SI for each femto base station according to a predefined equationusing unique ID information of femto base stations corresponding to theCSG, and unique ID information of the macro base station itself, andgenerates a measurement gap pattern for receiving the SI. Here, sincethe macro base station cannot perform communication with the UE duringthe measurement gap pattern, the macro base station should generate andrecognize the measurement gap pattern.

Next, the macro base station ends the operation according to anexemplary embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation procedure of a UE thatgenerates a measurement gap for receiving SI in a broadband wirelesscommunication system according to an exemplary embodiment of the presentinvention.

Referring to FIG. 7, in step 701, the UE enters a macro base stationincluding a femto base station corresponding to a CSG, and in step 703,transmits, to the macro base station, a registration message includingCSG information, i.e., information (for example, unique ID information)of femto base stations which the UE can access.

In step 705, the UE has its frame synchronized with a frame of the macrobase station, and in step 707, determines a transmission frame index ofSI for each femto base station according to a predefined equation usingunique ID information of femto base stations included in the CSG, andunique ID information of the macro base station, and generates ameasurement gap pattern for receiving the SI. At this point, themeasurement gap pattern may be generated with consideration of an errorin frame synchronization.

Next, the UE ends the operation according to an exemplary embodiment ofthe present invention.

In the descriptions of FIGS. 3 to 7, after determining a measurement gappattern for receiving SI, the UE searches for a relevant femto basestation every measurement gap determined above and receives the SI. Inaddition, rather than searching for the relevant femto base stationevery measurement gap, the UE may enter a region of the relevant femtobase station, receive a PCID, and receive SI according to the determinedmeasurement gap pattern as illustrated in FIG. 8.

FIG. 8 is a view illustrating a signal flow for reception of SI in abroadband wireless communication system according to an exemplaryembodiment of the present invention. FIG. 8 illustrates an operationafter a femto base station is installed.

Referring to FIG. 8, in step 810, UE 800 enters a macro base station 804with which a femto base station 802 corresponding to a CSG isassociated, and in step 812, transmits, to the macro base station 804, aregistration message including CSG information, i.e., information offemto base stations which the UE can access. In step 814, the UE 800 andthe macro base station 804 have their frames synchronized, and in steps816 and 818, independently determine a transmission frame index of SIfor each femto base station using unique IDs of femto base stationsincluded in the CSG, and a unique ID of the macro base station 804, andgenerate measurement gap patterns for receiving the SI, respectively.

In step 820, the UE 800 enters a region of a femto base station 802 andreceives a PCID from the femto base station 802, and in step 822,informs the macro base station 804 that the UE 800 has received the PCIDfrom the femto base station 802. In step 824, the macro base station 824transmits, to the UE 800, a signal allowing the UE 800 to search for afemto base station according to the generated measurement gap pattern.At this point, the UE 800 is implicitly assigned the measurement gap forreceiving SI by the femto base station 802.

In step 826, the UE 800 searches for the femto base station 802 duringthe measurement gap, and in step 828, enters a region of the femto basestation 802, and in step 830, receives the SI including a GCID from thefemto base station 802 during the measurement gap.

FIG. 9 is a block diagram illustrating a femto base station in abroadband wireless communication system according to an exemplaryembodiment of the present invention.

Referring to FIG. 9, the femto base station includes a transmitter 901,a receiver 903, a synchronizer 905, a controller 907, an SI transmissioncontroller 909, an SI transmission point determiner 911, a storing unit913, and a duplexer 915.

First, the duplexer 915 transmits a transmission signal provided fromthe transmitter 901 according to a duplexing scheme via an antenna, andprovides a reception signal from the antenna to the receiver 903.

The transmitter 901 up-converts a baseband signal provided from thecontroller 907 into a Radio Frequency (RF) signal and provides the RFsignal to the duplexer 915. The receiver 903 down-converts an RF signalreceived from the duplexer 915 via the antenna into a baseband signaland provides the baseband signal to the controller 907.

The synchronizer 905 synchronizes frames with frames of a macro basestation using signals transmitted/received to/from the macro basestation including the femto base station. That is, the synchronizer 915synchronizes frames such that index numbers of frames currentlytransmitted/received to/from the macro base station are substantiallymatched with each other.

The controller 907 controls and processes overall operations of thefemto base station. More particularly, the controller 907 providesunique ID information of the macro base station received via thereceiver 903 and unique ID information of the femto base station itselfstored in the storing unit 913 to the SI transmission point determiner911, and controls and processes a function of transmitting SI includinga GCID of the femto base station itself every transmission pointdetermined by the SI transmission point determiner 911 by including theSI transmission controller 909.

The SI transmission point determiner 911 determines SI transmissionpoint, i.e., a transmission frame index according to a predefinedequation using the unique ID information of the macro base stationreceived via the controller 907 and the unique ID information of thefemto base station itself while the femto base station is installed.

The storing unit 913 stores the unique ID information of the femto basestation itself. Here, the unique ID information of the femto basestation includes a GCID, a CSG ID, and a TA ID, and may includeinformation which combines the GCID, CSG ID, and TA ID.

FIG. 10 is a block diagram illustrating a macro base station in abroadband wireless communication system according to an exemplaryembodiment of the present invention.

Referring to FIG. 10, the macro base station includes a transmitter1001, a receiver 1003, a synchronizer 1005, a controller 1007, a messagemanager 1009, a measurement gap pattern generator 1011, a storing unit1013, and a duplexer 1015.

The duplexer 1015 transmits a transmission signal provided from thetransmitter 1001 according to a duplexing scheme via an antenna, andprovides a reception signal from the antenna to the receiver 1003.

The transmitter 1001 up-converts a baseband signal provided from thecontroller 1007 into a Radio Frequency (RF) signal and provides the RFsignal to the duplexer 1015. The receiver 1003 down-converts an RFsignal received from the duplexer 1015 via the antenna into a basebandsignal and provides the baseband signal to the controller 1007.

The synchronizer 1005 synchronizes frames with frames of a femto basestation included in a region of the macro base station itself, andsynchronizes frames with frames of UE that receives a service from themacro base station. That is, the synchronizer 1005 synchronizes framessuch that index numbers of frames currently transmitted/received to/fromthe femto base station and the UE are synchronized with each other.

The controller 1007 controls and processes overall operations of themacro base station. More particularly, the controller 1007 controls afunction of generating a message including unique ID information of themacro base station itself and transmitting the generated message to arelevant femto base station via the transmitter 1001, reads aregistration message received from UE via the receiver 1003 to obtainunique ID information of a femto base station corresponding to a CSG ofthe UE, and provides the obtained information to the measurement gappattern generator 1011 by including the message manager 1009.

The measurement gap pattern generator 1011 determines a transmissionpoint of SI, i.e., a transmission frame index according to a predefinedequation using the unique ID information of the macro base stationitself and unique ID information of a femto base station provided fromthe message manager 1009, and generates a measurement gap pattern forreceiving the SI based on the determined transmission frame index. Atthis point, the measurement gap pattern generator 1011 may generate themeasurement gap pattern with consideration of an error in framesynchronization.

The storing unit 1013 stores the unique ID information of the macro basestation itself. Here, the unique ID information of the macro basestation includes a GCID, a CSG ID, and a TA ID, and may includeinformation which combines the GCID, CSG ID, and TA ID.

FIG. 11 is a block diagram illustrating a UE in a broadband wirelesscommunication system according to an exemplary embodiment of the presentinvention.

Referring to FIG. 11, the UE includes a transmitter 1101, a receiver1103, a synchronizer 1105, a controller 1107, an SI reception controller1009, a message manager 1111, a storing unit 1113, a measurement gappattern generator 1115, and a duplexer 1117.

The duplexer 1117 transmits a transmission signal provided from thetransmitter 1101 according to a duplexing scheme via an antenna, andprovides a reception signal from the antenna to the receiver 1103.

The transmitter 1101 up-converts a baseband signal provided from thecontroller 1107 into a Radio Frequency (RF) signal and provides the RFsignal to the duplexer 1117. The receiver 1103 down-converts an RFsignal received from the duplexer 1117 via the antenna into a basebandsignal and provides the baseband signal to the controller 1107.

The synchronizer 1105 synchronizes frames with frames of a macro basestation, which the UE itself enters. That is, the synchronizer 1105synchronizes frames such that index numbers of frames currentlytransmitted/received to/from the macro base station are synchronizedwith each other.

The controller 1107 controls and processes overall operations of the UE.More particularly, the controller 1107 controls and processes a functionof receiving SI from a relevant femto base station every measurement gappattern determined by the SI reception controller 1109 by including theSI reception controller 1109. In addition, the controller 1107 controlsa function of generating a registration message including CSGinformation of the UE itself and transmitting the registration messageto the macro base station via the transmitter 1101, reads a messagereceived from the macro base station to obtain unique ID information ofthe macro base station, and provides the information to the measurementgap pattern generator 1115 by including the message manager 1111.

The storing unit 1113 stores an access allowance list (white list orfingerprint) including unique IDs of femto base stations which the UEcan enter, i.e., femto base stations which belong to a CSG, and a uniqueID of the macro base station with which the femto base station isassociated.

The measurement gap pattern generator 1115 determines a transmissionpoint of SI, i.e., a transmission frame index according to a predefinedequation using the unique ID information of the macro base station andunique ID information of a femto base station stored in the storing unit1113, and generates a measurement gap pattern for receiving the SI basedon the determined transmission frame index. At this point, themeasurement gap pattern generator 1115 may generate the measurement gappattern with consideration of an error in frame synchronization.

According to exemplary embodiments of the present invention, atransmission point of SI of a femto base station is determined based onunique ID information of the femto base station and unique IDinformation of a macro base station in a broadband wirelesscommunication system, UE and the macro base station generate measurementgap patterns representing an SI reception point, respectively.Accordingly, the SI may be received without a separate signaling messageexchange, and a service requiring a high Quality of Service (QoS), suchas VoIP, may be provided without interruption while a UE performs ahandover from the macro base station to a femto base station.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims and their equivalents.

1. A System Information (SI) transmission method of a femto base stationin a wireless communication system, the method comprising: receivingunique identification information of a macro base station with which afemto base station is associated; determining an SI transmission pointusing unique identification information of the femto base station itselfand the received unique identification information of the macro basestation; and transmitting SI comprising a Global Cell IDentifier (GCID)every SI transmission point.
 2. The method of claim 1, wherein thedetermining of the SI transmission point comprises: determining an SItransmission frame index of the femto base station using the uniqueidentification information of the macro base station and the uniqueidentification information of the femto base station; and determiningthe transmission point based on the determined transmission frame index.3. The method of claim 1, wherein the SI transmission point isdetermined using the equation:(Closed Subscriber Group (CSG) IDentifier (ID) of femto basestation+Physical Cell ID (PCID) of macro base station) modulo N, where Ndenotes a number of frames.
 4. A measurement gap pattern transmissionmethod of a macro base station, for informing user equipment of a SystemInformation (SI) transmission point of a femto base station in awireless communication system, the method comprising: receiving uniqueidentification information of at least one femto base station includedin a Closed Subscriber Group (CSG) from a user equipment; generating atleast one measurement gap pattern representing a point at which SI ofthe at least one femto base station is transmitted using uniqueidentification information of the macro base station itself and theunique identification information of the at least one femto basestation; and transmitting the generated at least one measurement gappattern to the user equipment.
 5. The method of claim 4, wherein thegenerating of the at least one measurement gap pattern comprises:determining an SI transmission frame index of the at least one femtobase station using the unique identification information of the macrobase station itself and the unique identification information of the atleast one femto base station; and generating the at least onemeasurement gap pattern based on the determined transmission frameindex.
 6. The method of claim 5, wherein the SI transmission frame indexof the at least one femto base station is determined using the equation:(CSG IDentifier (ID) of femto base station+Physical Cell ID (PCID) ofmacro base station) modulo N, where N denotes the number of frames.
 7. Amethod of user equipment which receives System Information (SI) of afemto base station in a wireless communication system, the methodcomprising: transmitting unique identification information of at leastone femto base station included in a Closed Subscriber Group (CSG) to amacro base station; generating at least one measurement gap patternrepresenting an SI reception point using unique identificationinformation of the macro base station and the unique identificationinformation of the at least one femto base station; and receiving SIfrom the at least one femto base station according to the generated atleast one measurement gap pattern.
 8. The method of claim 7, wherein thegenerating of the at least one measurement gap pattern comprises:determining an SI transmission frame index of the at least one femtobase station using the unique identification information of the macrobase station and the unique identification information of the at leastone femto base station; and generating the at least one measurement gappattern based on the determined transmission frame index.
 9. The methodof claim 8, wherein the SI transmission frame index of the at least onefemto base station is determined using the equation:(CSG IDentifier (ID) of femto base station+Physical Cell IDentifier(PCID) of macro base station) modulo N, where N denotes a number offrames.
 10. The method of claim 7, wherein the user equipment stores alist comprising the unique identification information of the at leastfemto base station included in the CSG, and unique identificationinformation of at least one macro base station with which the least onefemto base station is associated.
 11. A System Information (SI)transmission apparatus of a femto base station in a wirelesscommunication system, the apparatus comprising: a receiver for receivingunique identification information of a macro base station with which afemto base station is associated; a transmission point determiner fordetermining an SI transmission point using unique identificationinformation of the femto base station itself and the received uniqueidentification information of the macro base station; and a transmitterfor transmitting SI comprising a Global Cell IDentifier (GCID) every SItransmission point.
 12. The apparatus of claim 11, wherein thetransmission point determiner determines an SI transmission frame indexof the femto base station using the unique identification information ofthe macro base station and the unique identification information of thefemto base station, and determines the transmission point based on thedetermined transmission frame index.
 13. The apparatus of claim 11,wherein the transmission point determiner determines the SI transmissionpoint using the equation:(Closed Subscriber Group (CSG) IDentifier (ID) of femto basestation+Physical Cell IDentifier (PCID) of macro base station) modulo N,where N denotes a number of frames.
 14. A measurement gap patterntransmission apparatus of a macro base station, for informing userequipment of a System Information (SI) transmission point of a femtobase station in a wireless communication system, the apparatuscomprising: a receiver for receiving unique identification informationof at least one femto base station included in a Closed Subscriber Group(CSG) from a user equipment; a measurement gap pattern generator forgenerating at least one measurement gap pattern representing a point atwhich SI of the at least one femto base station is transmitted usingunique identification information of the macro base station itself andthe unique identification information of the at least one femto basestation; and a transmitter for transmitting the generated at least onemeasurement gap pattern to the user equipment.
 15. The apparatus ofclaim 14, wherein the measurement gap pattern generator determines an SItransmission frame index of the at least one femto base station usingthe unique identification information of the macro base station itselfand the unique identification information of the at least one femto basestation, and generates the measurement gap pattern based on thedetermined transmission frame index.
 16. The apparatus of claim 14,wherein the measurement gap pattern generator determines the SItransmission frame index of the at least one femto base station usingthe equation:(CSG IDentifier (ID) of femto base station+Physical Cell IDentifier(PCID) of macro base station) modulo N, where N denotes a number offrames.
 17. An apparatus of user equipment which receives SystemInformation (SI) of a femto base station in a wireless communicationsystem, the apparatus comprising: a transmitter for transmitting uniqueidentification information of at least one femto base station includedin a Closed Subscriber Group (CSG) to a macro base station; ameasurement gap pattern generator for generating at least onemeasurement gap pattern representing an SI reception point using uniqueidentification information of the macro base station and the uniqueidentification information of the at least one femto base station; and areceiver for receiving the SI from the at least one femto base stationaccording to the generated at least one measurement gap pattern.
 18. Theapparatus of claim 17, wherein the measurement gap pattern generatordetermines an SI transmission frame index of the at least one femto basestation using the unique identification information of the macro basestation and the unique identification information of the at least onefemto base station, and generates the measurement gap pattern based onthe determined transmission frame index.
 19. The apparatus of claim 17,wherein the measurement gap pattern generator determines the SItransmission frame index of the at least one femto base station usingthe equation:(CSG IDentifier (ID) of femto base station+Physical Cell IDentifier(PCID) of macro base station) modulo N, where N denotes a number offrames.
 20. The apparatus of claim 17, further comprising a storing unitfor storing a list comprising the unique identification information ofthe at least one femto base station, and unique identificationinformation of at least one macro base station with which the least onefemto base station is associated.